I found an antique letter dial lock of this sort a year or two ago, and have been looking for another since--so lovely, and why ever would we have decided it was better to remember numbers than letters/words??? 18th or perhaps 19th century French, brass and iron/steel, with a nice weight to it, and satisfying tension to the turning of the dials when one gets close to lining up the letters that unlock it. And with a star among the letters on the fifth dial, which feels like a happy thing. (The combination to unlock it is DOMS*.) 

1 3/8" x 1 5/8" x 3/4" and in very good antique condition and completely functional as a lock. Marked (impressed) with the number 3 on one side as detailed.